Satellite Delay Simulator - sds
General Description:
The Satellite Delay Simulator (SDS) allows high-speed sampling and delaying of the input data in order to realize typical satellite delays and variations. The SDS has an on-board oscillator, which uses the external 10MHz reference and operates at 440MHz. The 440MHz-sampling rate allows direct IF interfacing to the system.
The input signal is sampled with an 8-bit A/D at the operating frequency. Each 8-bit sample is stored in 16-sample (128-bit) words in the main memory. The main memory consists of 96Mbytes of high-speed SRAM. The memory words are read out and re-converted through an 8-bit D/A on the output. The main memory is split into 3 banks. The banks are written to and read from continuously. The delays between the read and the write pointers are always maintained so that the same bank is never being read and written to at the same time. This mechanism supports the operating range of 110.0ms to 150.0ms. Additionally, the SDS supports a bypass mode (= 500ns). This is the default power-up condition.
Once a new profile is started, the SDS can change the delay (increment or decrement) by a single sample. This means that the delay can be changed by 2.2727ns for each increment or decrement. In the case of an increment, the same sample is repeated for one extra time sample (2.2727ns). In the case of a decrement, a single sample is dropped from the output. The timing for dropping or adding of a sample can be synchronized to an external signal to prevent samples being changed randomly with respect to the signal carrier.
When running a variable profile, the SDS interpolates the rate of change over time. For example, if the user selects a rate of change of 100ns then the SDS interpolates and makes (approx) 100.0 / 2.2727 = 44 changes per second. This interpolation provides the smoothest variation of the profile over time.
Features:
 | User programmable delays between 110ms and 150ms with a resolution of 2.27 ns |
| 440 MHz sampling rate with 8 bit samples |
| 80 Mhz bandwidth |
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Satellite orbit simulation is supported by sinusoidal changes of ± 20.10e6 * sin (2p t/24.3600) ns where t is in seconds, with a resolution of 2.27ns in each path |
| A maximum inclined orbit simulation is supported by linear changes of up to ± 200ns/sec with a resolution of 2.27ns in each path. |
| Delay changes are performed smoothly by adding in and dropping 1 sample at the profile rate |
| All control settings are set via a simple Windows® based GUI operating under Microsoft Windows® running on an external PC with |
a 9-pin RS-232 interface
| User programmable delay modes: Bypass (No Delay), Linear / Limit Profile, Linear / Cyclic Profile and fixed delay |
| Gain is user programmable from 0 to 20 dB. At maximum gain, -17 dBm input achieves full-scale output |
Intelsat Recommendation:
Hollis Electronics Company LLC (HEC) has developed a Satellite Delay Simulator, which allows users to test ground satellite equipment and/or in orbit systems before use on an actual satellite. Intelsat, a global communications leader, used the Hollis Electronics Company LLC Satellite Delay Simulator to test their new Time Division Multiple Access (TDMA) infrastructure system. Friedrich Luz, TDMA Program Manager at Intelsat stated, "Hollis Electronics held many of the attributes we look for in a supplier. – – – Their product granted us ease of use, performance, product reliability, and great customer support, which are all critical factors in being able to successfully test the equipment in-plant prior to actual deployment in the field."
About Intelsat:
Intelsat, Ltd. offers telephony, corporate network, video and Internet solutions around the globe via capacity on 25 geosynchronous satellites in prime orbital locations. Customers in approximately 200 countries and territories rely on Intelsat satellites and staff for quality connections, global reach and reliability. For more information, visit www.intelsat.com.